Fuel injector



Nov. 26, 1929. i E. R. HEwlTT 1,737,155

FUEL INJECTOR Filed June 28, 1927' "y my a I i F1913 p; "T l\ 4 J l A. Mmmm/p:

Edwafzljaudl Patented Nov. 26, 1929 UNITED STATES PATENT OFFICE EDWARD 2R', HEWITT, 0F MIDVALE, NEW' JERSEY, ASSIGNOR TO I-NTERNATINAI:

:MOTOR COFZIIPANY,r F N EW YORK, N. Y., A CORPORATION OF DELAWARE FUEL rmncron ipplicaton led June 28,

The present invention relates to devices for injecting fuel into a combustion space and includes injectors wherein a plunger is maintained seated by a suitable spring, the pressure of which is overcome by the fuel column to unseat the plunger and inject a quantity of the fuel within the space.

of bringing about an efficient mixture so that no particles of liquid fuel will collect on the walls of the chamber but, on the contrary, the fuel will be injected. in the form of a finely divided volume of vapor, each particle. of which is available for complete combus? tion has, caused considerableattention and resulted in devices which, at best, only partially overcome the above dificulty.

An object of the present invention is to provide an injector for liquid fuel which is able to finely atomize the charge and cause its intimate mixture with the desired volume of air to produce an explosive charge which can be fully burned and thereby approach, as closely as possible,`the maximum eciency obtainable for a given set of conditions. vllhe specific means by which this is accomplished includes an injector resembling, generally, old forms, but which is provided with a nozzle constructed with a tapering plunger seat and providing the plunger with an outer surface or extension forming, preferably an acute angle with the face of the injector.'

A further object of the invention is to iinprove the construction of the injector to render it more rugged and enable it to feed the fuel without becoming clogged by foreign mattei' which may be present therein. Other objects will appear as the description proceeds and reference will now be had to the accompanying drawings for a more detailed description of the invention wherein: Figure l is an elevation, in section, showing a prefered formof the invention.

Figure 2 is a section taken on line 2-2 of '1927. serial no. 202,059.

Figure l and looking in the direction of the arrows. l

Figure 3 is a view in elevation, partly in section, showing an enlarged plunger and related valve seatas shown 1n Figure l.,

Figure l is a view in elevation, partly in section, showing a modification of Figure 3, i Referring to the drawings', a designatesthe casing of an injector having a hollow cylindrical bearing portion a', an extension z2 adapted to be secured to a cylindrical head construction in well known manner, and female threads as, At the' lower extremity of extension a2, a conical seat is provided against which a suitable extension 5 on plunger b may be seated.

Secured at the top of the casing is a fitting a4 which receives a nipple a5 and is provided with a manually operated tap as. Channels a7 are provided in the fitting and afford a means of communication between the hollow portion a8 of the fitting and the air. By means of tap a, any air collected in the hollow portion as may be kblown out as will be readily understood from the drawings.y 'llhe nipple a5 isprovided with a threaded eXten- -sion a9 to which a feed line c may be conf n nected by means or a sultable nut c 'and packing c2. j

rllhe plunger b is -provided with a threaded end b2 which receives a nut b3. Between the nut and the upper portion the casing a, a

spring l is secured. This spring serves to seat the extension L of the plunger upon the conical seat at the bottornof the exten-- sion a2 of the casing, and its tension may be I varied by means of the nut 63. rlhe plunger is formed with longitudinal grooves which permit the flow of fluid from the hollow portion as to the end of the extension a2.

lt will be apparent lthat a differential pressure exists between spring d and the fuel supply from pipe c, and when the pressure of the fuel supply in pipe c is sufficient, the plunger will be moved downwardly, against the action of spring al, to unseat the extension b ofthe-plunger from the conical seat in the extension a2 ofthe cas/ing, lAs long as this excess pressure is sustained, the vfuel will be ejected from the casing, and

when removed, the plunger will be seated once more to prevent further flow of the fuel.

In order to atomize, more eectively, the spray ,of the injector, the extension b is formed with an outwardly slanting conical surface 55 which engages the top of the conical nozzle 57 in the extension a2 of the casing. Beyond such conical portion, a further extension be is provided in the form of a second truncated cone, Figurel 4 or a cylinder, Figure 3 the sides of which preferably lie at angles of 10 with the surface b5 of the' plunger. 1t has been found that best results are obtained when the lateral slant ci the conical nozzle 57 of the casing a: is about 30 with respect to the centerline of the plunger,

and the sides of the .truncated extension lie at angles of 10 with respect to the surface The angle of lateral slant of the portion t5 may be Varied between certain limits and 4in order to eiect better seating of the plunger,- the sides b5 should be at an appreciable anglev to the surface b'f of the injector so that a line contact between the two will result. lli, as in Figure 1l, the angle of the side of 55 to the length of the plunger is increased, the face 57 must be flared out accordingly 'to keep an angle of say 20 between the face o? and b5 to allow room for the spraying of the fuel between the two.

. It has been found that making the angle of lateral slant of the, truncated or cylindrical section less than that of b5 the atomization is improved tremendously, this being the essential feature of the invention.

v As a further feature, itis to be noted that the bearing portion at of the casing a serves to constrain, positively, the 'movements of the plunger b to eect the proper seating of its conical portion b5 and thus cause a positive cut-off of the spray at the desired point.

By providing impulses of suicient suddenl ness and pressure, through the supply pipe c', the resulting spray 'into the combustion chamber is of a finely atomized character and in the form of a vwell defined volume which has been regulated by the proper seating of the plunger b.

Although the invention has been described with reference to the specific embodiment shown in the accompanyin drawings, wherein certain dimensions have een given as preferable, it is to be understood that the invention is `not to be limited in respect to the dimensions and arrangement of the parts, save as defined in the appended claims,

What I claim is: y

l. In .a device for spraying. fluids, a casing having a nozzle in the shape of a truncated cone of outward lateral slant, a plunger movable in the casing, a truncated conical eX- tension on the plungensaid extension being positioned to seat against the nozzle and being of appreciably less outward vlateral slant than said nozzle,i .whereby a line contact between these will result when the extension is seated and an outwardly enlarging passage for fluid will exist, and a prolongation on the extension, said prolongation havmg generally circular cross-section and an upward lateral slant of from zero degrees upwards but less than that of the extension.

2. ln a device for spraying fluids, a casing having a nozzle in the shape of a truncated cone of outward lateral slant, a plunger movable in the casing, a truncated conical extension on the plunger, said extension being positioned to seat against the nozzle and being of appreciably less outward lateral slant than said nozzle, whereby a line contact between these will result when the extension is seated and an outwardly enlarging passage for Huid will exist, and a prolonga- 'tion on the extension, the outer periphery of the extension andthe inner periphery of the 

